Fluorine-free fire fighting agents and methods

ABSTRACT

A foam concentrate provides a fire-fighting composition when mixed with water so that the fire-fighting composition does not form a stable seal on cyclohexane and meets UL  162 , Class B performance criteria for at least one of AFFF agents and fluoroprotein (FP) agents without requiring organic fluorine. The concentrate is formed from water and a high molecular weight acidic polymer (HMWAP) and a coordinating salt.

TECHNICAL FIELD

The invention relates generally to fire-fighting agents.

BACKGROUND

Aqueous film forming foam (AFFF) agents are known for the rapidextinguishment of Class B fires and enhancement of safety by providingflashback or burnback resistance. First described by Francen in U.S.Pat. No. 3,562,156, AFFF agents by definition must have a positivespreading coefficient on cyclohexane. Many US patents describe thecomposition of AFFF agents which meet the positive spreading coefficientcriteria, such as U.S. Pat. Nos. 4,420,434; 4,472,286; 4,999,119;5,085,786 and 5,218,021; 5,616,273.

The prior art relating to AFFF agents has one common element; therequirement of various quantities and types of fluorochemicalsurfactants to obtain the positive spreading coefficient when combinedwith various hydrocarbon surfactants. U.S. Pat. No. 5,616,273 describespresent AFFF and alcohol resistant aqueous film forming (AR-AFFF) agentsused to generate aqueous film forming foams having fluorine contentsranging from 0.020 to 0.044 percent in premix form. The actual fluorinelevel has been dependant on the required performance specifications,with higher fluorine content providing faster extinguishing performanceand greater burn back resistance. The lowest fluorine content product(0.020% F) would contain about 1.3% by weight fluorochemical surfactantsolids in the 3% liquid concentrate since these products contain about50% by weight fluorine.

The criterion necessary to attain spontaneous spreading of twoimmiscible liquids has been taught by Harkins et al, Journal Of AmericanChemistry, 44, 2665 (1922). The measure of the tendency for spontaneousspreading of an aqueous solution over the surface of non-polar solventssuch as hydrocarbons is defined by the spreading coefficient (SC) andcan be expressed as follows:SC_(a/b)=γ_(a)−γ_(b)−γ_(c), where  1)

-   -   SC_(a/b)=Spreading Coefficient;    -   γ_(a)=Surface tension of the lower hydrocarbon phase;    -   γ_(b)=Surface tension of the upper aqueous phase; and    -   γ_(c)=Interfacial tension between the aqueous upper phase and        the lower hydrocarbon phase.

If the SC is positive, in theory an aqueous solution should spread andfilm formation on top of the hydrocarbon surface should occur. The morepositive the SC, the greater the spreading tendency will be. Inpractice, however, it has been found that no visible film seal occurs oncyclohexane until the SC is greater than about +3.5 to about 4.0,especially if the fluorochemical content is low. It is further knownfrom the art that γ_(a) is reduced as the temperature of the hydrocarbonis increased, as occurs during the burning of these fuels. This willlower the effective SC during fire extinguishing unless the fireextinguishing solution also has decreasing γ_(b) on increasingtemperature.

Fluorochemical surfactants have recently come under scrutiny by the EPAand environmental groups. In fact, at least one major manufacturerrecently agreed to stop the manufacture of Perfluorooctanesulfonate(PFOS) and Perfluorooctanoic acid (PFOA) based products includingfluorinated surfactants used in AFFF and AR-AFFF agents. The EPA, priorto May 2000, had determined that PFOS posed a long-term threat to theenvironment after PFOS was found in all animals tested and wasdetermined to be toxic after various long-term feeding studies. The EPAhas since initiated a program requiring other perfluorochemicalproducers to supply information on their products to the EPA. This wouldallow the EPA to evaluate potential environmental problems from otherfluorochemical surfactants already in the marketplace.

It may therefore be desirable to have fire extinguishing products whichdo not contain fluorine-containing compounds, while still extinguishingClass B fires as effectively as AFFF agents.

The instant invention provides compositions that require little or nouse of fluorochemical surfactants or other fluorine containingcompounds, yet the novel fire fighting liquid concentrates still meet orexceed Fluoroprotein (FP) and Aqueous Film Forming Foam agent (AFFF)performance criteria on Class B, UL162 fires. If fluorochemicalsurfactant use is severely curtailed by the EPA, these agents could beimportant for the future of firefighting in the United States.

The commercial AFFF agent market in the United States consists mostimportantly of products which are UL listed such that consumers can beassured of minimum performance characteristics of AFFF agents. The UL162 Standard for Safety covers Foam Equipment and Liquid Concentrates.Section 3.16, UL162 (Seventh edition, 1997) defines six liquidconcentrates recognized by UL as low expansion liquid concentrates. Parta) defines Aqueous Film Forming (AFFF) as “a liquid concentrate that hasa fluorinated surfactant base plus stabilizing additives.” Part b)defines Protein as “a liquid concentrate that has a hydrolyzed proteinplus stabilizing additives.” Part c) defines Fluoroprotein (FP) as “aliquid concentrate that is similar to protein, but with one or morefluorinated surfactant additives.” Part d) defines Film FormingFluoroprotein (FFFP) as “a liquid concentrate that has both a hydrolyzedprotein and fluorinated surfactant base plus stabilizing additives.”Part e) defines Synthetic as “a liquid concentrate that has a base otherthan fluorinated surfactant or hydrolyzed protein. Finally Part f)defines Alcohol Resistant as “a liquid concentrate intended toextinguish both hydrocarbon and polar (water miscible) fuel fires.”

Fire test foam application and duration to burnback ignition is given inUL 162 Table 10.1 for Class B fire tests. These minimum performancecriteria must be met for liquid concentrates to be “UL listed” as ClassB liquid concentrates. Of the six liquid concentrates defined by UL 162,only protein and synthetic do not contain fluorosurfactant and, ofthese, only protein has UL listed 3% products for use on Class B liquidfires. At this time, synthetic liquid concentrates are mainly UL listedas wetting agents and defined by UL as “liquid concentrates which, whenadded to plain water in proper quantities, materially reduce the surfacetension of plain water and increases its penetration and spreadingability . . . Listed wetting agents solutions or foams improve theefficiency of water in extinguishing fires.”

Only one synthetic, SYNDURA, commercialized by Angus Fire Armour is ULlisted on Class B fires at 6% dilution rate and at the fluoroproteinapplication rate. Syndura utilizes a polysaccharide stabilizing agent,and although marketed as “operationally fluorine-free,” it does containat least some fluorine.

DETAILED DESCRIPTION

The present invention provides fire fighting concentrates of thesynthetic type which meet and exceed UL listing requirements for use onClass B fires as listed in UL162 that may have “zero” fluorine content.Further, these products may be used at 3% concentrate level. Nofluorosurfactants or fluorinated polymers are required to meet the UL162standard but may be used to improve extinguishing speed and burnbacktimes, if desired. The compositions for use as fire extinguishingconcentrates can meet or exceed Fluoroprotein (FP) and AFFF performancecriteria on Class B, UL162 non-polar (water insoluble) liquid fires, butwithout the need of fluorochemical surfactants or polymers, as requiredin the prior art. These compositions include synthetic liquidconcentrates stabilized with high molecular weight acidic polymers(HMWAP) and coordinating salt(s), which extinguish non-polar Class Bfires. No fluorosurfactants or fluorinated polymers are required to meetthe UL 162 standard, but may be used to improve extinguishment speed andburnback times, if desired. Thus, as used herein, the expression“without requiring fluorine” or “without requiring organic fluorine” ismeant to cover those situations wherein the composition provides thestated performance absent such fluorine or organic fluorine componentsthat might otherwise be included, with all other components and relativequantities of such components (other than the specified fluorine)remaining the same, and does not preclude that fluorine or organicfluorine may be included in such compositions.

The invention further provides a method of extinguishing Class Bnon-polar liquid fires using the fire fighting compositions withoutrequiring or having no added fluorochemical surfactants or fluorinatedpolymers, or with very low fluorochemical surfactants or fluorinatedpolymer content. This method provides fast extinguishment and burnbacksimilar to that provided by FP agents, as well as, AFFF agents havinghigh fluorochemical surfactant content. And although Class B liquid fireperformance (UL162) for such agents is achieved without requiringfluorine-containing compounds, fluorine-containing compounds may stillbe used, if desired.

It has been found that synthetic liquid concentrate can be stabilized toClass B liquid fire performance (UL 162) with the addition of variousfoam stabilizing acidic polymeric additives in conjunction withcoordinating salts. The effectual HMWAP additive and the effective levelnecessary for improving the synthetic liquid concentrate can be readilyidentified and determined through a straightforward laboratory test.Salts of interest would include those of Aluminum, Antimony, Barium,Boron, Calcium, Copper, Iron, Magnesium, Strontium, Thallium, Tin,Titanium, and Zinc. Salts having oxidation states of +2 and +3 are mostuseful; and include salts of Aluminum, Boron, Calcium, Iron, Magnesiumand Zinc.

HMWAPs may include those containing multiple carboxylic acid groups orother functionally acidic groups, such as sulfonic and phosphoricgroups. Such polymers include but are not limited to polymers orcopolymers prepared by the polymerizing of monomers, which may have oneor more acidic functional groups thereon, and that provide hydrophobicgroups, which may be in the form of alkyl branches or tails along thepolymer chain of from C4 to C22 or greater. As used herein, “polymer”refers to homopolymers or copolymers, and the term “copolymer” refers tothose polymers prepared from the polymerization of two or moredissimilar monomers. The HMWAP may also be prepared from linear ornon-linear polymers wherein alkyl branching or tails are provided afterpolymerization of the main polymer chain. The acidic functional groupsmay also be provided after formation of the branched polymer chain. Thevarious methods of preparation of such HMWAP are well known to thoseskilled in the art.

As stated, the HMWAP have alkyl branches or tails of from C4 to C22 orgreater, some or all of which may contain acidic functional groups. Thepolymers, however, may contain alkyl groups with chains of C4 to C 18length, more particularly, polymers containing multiple alkyl groupswith chains of C8 to C 16 length. The HMWAP may have an averagemolecular weight of from about 5000 to about 2,000,000 or greater. Incertain embodiments, the HMWAP may have an average molecular of fromabout 20,000 or 30,000 to about 1,000,000.

Effective in stabilizing the synthetic liquid concentrate foam bubble toClass B liquids are HMWAPs containing hydrophobic groups, moreparticularly C8 to C16 alkyl substituents including commercial products,such as Chemguard HS-100, available from Chemguard, Inc. Mansfield, Tex.Chemguard has used HS-100 since 1999 in combination with ChemguardFS-100 (fluorinated surfactant) to make especially efficient AFFFagents. Chemguard HS-100 is an HMWAP surfactant of unknown exactstructure which increases foam expansion, drain time, and fluidity inthe AFFF formulation. In 3% AFFF agents, HS-100 is used at less thanabout 0.7% actives in all formulations to obtain optimal performance andformulations typically contain only 1-2% hydrated magnesium sulfate.

When Chemguard HS-100 (HMWAP), which may be used at 2-4% actives, andhydrated magnesium sulfate, which may be used at approximately 15-30%,is used in 3% synthetic liquid concentrates, excellent Class B, UL162fire performance is obtained without the addition of fluorochemicalsurfactants or fluorine containing compounds. Unless otherwise specifiedall percentages presented herein are by weight. When HS-100 is used atthe lower level, greater quantities of magnesium sulfate may berequired, while lower levels of magnesium sulfate are effective whenhigher levels of HS-100 are used. If desired, higher levels of ChemguardHS-100 and magnesium sulfate may be used to provide even strongerperformance and weaker but still well performing products can be madeusing lower quantities of these products.

The composition may be used for providing training foams. An example ofa training foam product includes 0.9% actives Chemguard HS-100 and about10% magnesium sulfate, which may be used as 3% training foams.Similarly, 1% training foams without environmental problems, exceptpossibly for foam, can be prepared with about 2.7% actives ChemguardHS-100 and 30% magnesium sulfate.

The present invention has application to fire extinguishing compositionsuseful for extinguishing UL 162 Class B non-polar (water insoluble)liquid fires by the addition of effectual HMWAP and coordinating saltsto various synthetic liquid concentrates at effective levels. Thecomposition of HMWAP and polyvalent salts as here defined could also beused in low protein content products (i.e. less than 10% protein byweight).

The instant invention further provides a method of extinguishing Class Bfires using the fire fighting compositions having no addedfluorochemical surfactant or other compounds containing fluorine. Thismethod provides fast extinguishment and burn back similar to thatprovided by FP agents, as well as, AFFF agents having highfluorochemical surfactant or other fluorine content. The concentratesmay be educted at 6% or 3% into water, either fresh, brackish, or seawater, and applied to the fire from aspirated or non-aspirated devices,foam chambers, or sprinkler systems. As used herein, the term “water”may include pure, deionized or distilled water, tap or fresh water, seawater, brine, or an aqueous or water-containing solution or mixturecapable of serving as a water component for the fire fightingcomposition.

AFFF and FP agents are known as excellent foams for extinguishingnon-polar Class B fires; however, the presence of fluorosurfactants isseen by many as a potential environmental hazard. The present inventionprovides a means of extinguishing these difficult fires without the useof either fluorosurfactants or other fluorine containing compounds andtherefore does not pose an environmental hazard, other than foam.

The use of HMWAP and coordinating salts is advantageous, in part, due tothe well established lower toxicity of polymers relative to monomericcompounds. In fact, it is much easier to list polymers (none reactive)on the TSCA inventory than low molecular weight materials due to thisfact. Similarly, in Europe, polymers are exempt from the EINICS list. Itis widely understood that as polymers increase in MW, their absorptionrate through skin decreases. Further, high MW polymers rapidly adsorb tosolid surfaces such as dirt, rocks, etc, and are much less available forentering water ways. Therefore, they are in general more environmentallybenign than low MW surfactants and chemicals.

The present invention is readily extended to provide fire extinguishingagents having exceptional performance if small amounts offluorosurfactants or high molecular weight fluorinated polymers(HMWFPs), as described in U.S. patent application Ser. No. 10/213,703for Fire Extinguishing or Retarding Material are included in theseformulations, and which is herein incorporated by reference.

The claimed synthetic surfactant liquid compositions may be produced atmany strengths, including but not limited to 3 and 6% foam concentrates.The lowest numbered strength is actually the most concentrated product.Therefore, three parts of 3% and 97 parts water gives 100 parts of usestrength pre-mix, whereas, six parts 6% and 94 parts water gives 100parts of pre-mix.

For the sake of simplicity only 3% products will be exemplified here,while it is understood that many other strength products are included. Ageneral composition for a 3% liquid concentrate (used at 3 partsconcentrate to 97 parts fresh or tap water) is as follows: % by weightComponent (100%) A High molecular weight acidic polymer 0.9-6 (HMWAP) BCoordinating salt   4-40 C Amphoteric Hydrocarbon Surfactant   0-3 DAnionic Hydrocarbon Surfactant   2-12 E Nonionic Hydrocarbon surfactant  0-5 F Fluorochemical Surfactant   0-0.4 G Foam aids including glycolethers   0-15 H Freeze protection package   0-45 I Sequestering, buffer,corrosion package   0-5 J Polymeric film formers   0-2 K Biocides,antimicrobial   0-0.1 L Polymeric foam stabilizers and thickeners   0-10M Water Balance

The above components would be reduced accordingly relative to the 3%liquid concentrate to prepare 6% synthetic liquid foam concentrates.

Most Class A foam concentrates fit within the definition of the basesurfactant defined above. Therefore, addition of an effectual HMWAP andcoordinating salt (as defined from the laboratory test) has applicationto many Class A foam concentrates as well.

Similarly, an effectual HMWAP and coordinating salt may also be added to3 or 6% liquid protein concentrate containing no or trace fluorochemicalsurfactant

The HMWAP (Component A) and polyvalent coordinating salt (Component B)are chosen using the laboratory test described in the experimentalsection. In general these are products prepared from monomers, eithermono- or polyfunctional, polymerized with reactive polyfunctionalmonomers, prepolymers or high MW polymers with appropriate reactivesites. Hydrophobic and acidic sites may be formed within the polymer byinclusion with the monomers or by addition to the formed polymer, suchas reaction of sodium monochloroacetate with amine residues. Examples ofpolymers for consideration using the defined performance test aredescribed in U.S. Pat. Nos. 6,528,575 B1; 6,361,768 B1; 6,284,855 B1;6,090,894; 5,039,433, 4,683,066; 4,474,916; 4,500,684; 4,908,155;4,317,893; 4,284,517, which are herein incorporated by reference.

A suitable commercially available HMWAP (Component A) is ChemguardHS-100, a high MW acidic polymer having multiple C12 alkyl tails andmultiple carboxylic acid groups.

Component B include electrolytes and coordinating salts, added tocoordinate with the above Component A HMWAPs to stabilize the foambubble to fire and hot solvents. Typical electrolytes and salts mayinclude those of Aluminum, Antimony, Barium, Boron, Calcium, Copper,Iron, Magnesium, Strontium, Thallium, Tin, Titanium, and Zinc. Saltshaving oxidation states of +2 and +3 are suitable. Included are thealkaline earth metals, especially magnesium, calcium, strontium, andzinc or aluminum. The cations of the electrolyte are not critical,except that halides may be undesirable from the standpoint of metalcorrosion. Sulfates, bisulfates, phosphates, nitrates and the like arealso acceptable. As used herein, the expression “coordinating salt” ismeant to include both salts and electrolytes.

Particularly useful are polyvalent salts such as magnesium sulfate andmagnesium nitrate.

The amphoteric hydrocarbon surfactants (Component C) include but are notlimited to those which contain in the same molecule, amino and carboxy,sulfonic, sulfuric ester and the like. Higher alkyl (C6-C14) betainesand sulfobetaines are included. Examples of commercially availableproducts include Chembetaine CAS and Mirataine CS, both sulfobetaines,MacKam 2CYSF and Deriphat 160C, a C 12 amino-dicarboxylate. Theseproducts are excellent foaming agents and help reduce interfacialtension in water solution.

Anionic hydrocarbon surfactants (Component D) include but are notlimited to alkyl carboxylates, sulfates, sulfonates, and theirethoxylated derivatives. Alkali metal and ammonium salts may also beused. Anionic hydrocarbon surfactants in the C8-C 16, C8-C 12, and C8-C10 range are particularly useful.

The nonionic hydrocarbon surfactants (Component E) help reduceinterfacial tension and solubilize other components, especially in hardwater or sea water solutions. In addition, they serve to control foamdrainage, foam fluidity, and foam expansion. Suitable nonionicsurfactants include but are limited to polyoxethylene derivatives ofalkylphenols, linear or branched alcohols, fatty acids, alkylamines,alkylamides, and acetylenic glycols, alkyl glycosides and polyglycosidesas described in U.S. Pat. No. 5,207,932 and others, and block polymersof polyoxyethylene and polyoxypropylene units.

Fluorochemical surfactants (Component F), which may be useful at lowlevels, are found in the many AFFF patents including but not limited tothose described in U.S. Pat. Nos. 5,616,273, 5,218,021; 5,085,786;4,999,119; 4,472,286; 4,420,434; 4,060,489, which are hereinincorporated by reference.

Small quantities of fluorochemical surfactant may be added to increaseextinguishing speed and burnback resistance. But in all instances, thetotal fluorochemical surfactant content is limited to less than one-halfnormal workable levels in the absence of the inventive matter to provideUL 162 Class B fire performance. This means less than about 0.20%fluorine as fluorochemical surfactant in a 3% concentrate or less thanabout 0.006% fluorine at the working strength. This compares veryfavorably with data of U.S. Pat. No. 5,207,932 leading to a commercialproduct with low end working fluorine content of 0.013% fluorine (a 55%reduction in fluorine content).

Foam aids (Component G) are used to enhance foam expansion and drainproperties, while providing solubilization and anti-freeze action.Useful solvents are disclosed in U.S. Pat. Nos. 5,616,273, 3,457,172;3,422,011 and 3,579,446, which are herein incorporated by reference.

Typical foam aids are alcohols or ethers such as: ethylene glycolmonoalkyl ethers, diethylene glycol monoalkyl ethers, propylene glycolmonoalkyl ethers, dipropylene glycol monoalkyl ethers, triethyleneglycol monoalkyl ethers, 1-butoxyethoxy-2-propanol, glycerine, andhexylene glycol.

The freeze protection package (Component H) may include glycerine,ethylene glycol, diethylene glycol, and propylene glycol. Also includedare salts and other solids which reduce freeze point such as calcium,potassium, sodium and ammonium chloride and urea.

Component I, the sequestering, buffer, and corrosion package, aresequestering and chelating agents exemplified by polyaminopolycarboxylicacids, ethylenediaminetetraacetic acid, citric acid, tartaric acid,nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid andsalts thereof.

Buffers are exemplified by Sorensen's phosphate or Mcllvaine's citratebuffers. Corrosion inhibitors are only limited by compatibility withother formula components. There may be exemplified byortho-phenylphenol, toluyl triazole, and many phosphate ester acids.

Components J is a water soluble polymeric film former and may be usedfor the formulation of AR (alcohol resistant) agents which are used tofight both polar (water soluble) and non-polar solvent and fuel fires.These polymeric film formers, dissolved in AR agents, precipitate fromsolution when the bubbles contact polar solvents and fuel, and form avapor repelling polymer film at the solvent/foam interface, preventingfurther foam collapse. Examples of suitable compounds includethixotropic polysaccharide gums as described in U.S. Pat. Nos.3,957,657; 4,060,132; 4,060,489; 4,306,979; 4,387,032; 4,420,434;4,424,133; 4,464,267, 5,218,021 , and 5,750,043, which are hereinincorporated by reference. Suitable commercially available compounds aremarketed as Rhodopol, Kelco, Keltrol, Actigum, Cecal-gum, Calaxy, andKalzan.

Gums and resins useful as Component J include acidic gums such asxanthan gum, pectic acid, alginic acid, agar, carrageenan gum, rhamsamgum, welan gum, mannan gum, locust bean gum, galactomannan gum, pectin,starch, bacterial alginic acid, succinoglucan, gum arabic,carboxymethylcellulose, heparin, phosphoric acid polysaccharide gums,dextran sulfate, dermantan sulfate, fucan sulfate, gum karaya, gumtragacanth and sulfated locust bean gum.

Neutral polysaccharides useful as Components J include: cellulose,hydroxyethyl cellulose, dextran and modified dextrans, neutral glucans,hydroxypropyl cellulose, as well, as other cellulose ethers and esters.Modified starches include starch esters, ethers, oxidized starches, andenzymatically digested starches.

Components K, antimicrobials and preservatives, may be used to preventbiological decomposition of natural product based polymers incorporatedas Components J. Included are Kathon CG/ICP and Givgard G-4-40manufactured by Rohm & Haas Company and Givaudan, Inc., respectively, asdisclosed in U.S. Pat. No. 5,207,932. Additional preservatives aredisclosed in the above polar agent patents—U.S. Pat. Nos. 3,957,657;4,060,132; 4,060,489; 4,306,979; 4,387,032; 4,420,434; 4,424,133;4,464,267, 5,218,021, and 5,750,043, which are herein incorporated byreference.

Components L are polymeric foam stabilizers and thickeners which can beoptionally incorporated into AFFF and AR-AFFF agents to enhance the foamstability and foam drainage properties. Examples of polymericstabilizers and thickeners are partially hydrolyzed protein, starches,polyvinyl resins such as polyvinyl alcohol, polyacrylamides,carboxyvinyl polymers, polypyrrolidine, and poly(oxyethylene) glycol.

Many commercial synthetic surfactant concentrates are marketed worldwideby Chemguard, Kidde, and Tyco. The addition of an effectual high MWacidic polymer and coordinating salt to these liquid concentrates at aneffective concentration may be encompassed by the present invention.These products include: Class A foams (CLASS A PLUS and SILVEX),excellent for extinguishing forest fires, structural fires, and tirefires; High expansion foams sold under the names HI-EX, EXTRA, C2, andVEE-FOAM; Vapor suppressant foam sold by Chemguard as VRC foam; Bombfoam, a 6% product sold by Chemguard as AFC-380.

Synthetic surfactant concentrates listed as “wetting agents” byUnderwriters Laboratory are also included as base surfactant mixturesfor use in this invention. Products listed by UL as “wetting agents”include the following: Fire Strike by Biocenter Inc.; Bio-Fire byEnvirorenu Technologies LLC; Enviro-Skin 1% by Environmental ProductsInc.; F-500 by Hazard Control Technologies Inc.; Knockdown by NationalFoam Inc.; Phos-Chek WD881 by Solutia Inc.; Flameout by SummitEnvironmental Corp. Inc. Micro-Blazeout by Verde Environmental Inc.;Bio-solve by Westford Chemical Corp.

EXAMPLES

In the examples below, references are made to specifications used by theindustry to evaluate the efficiency of synthetic surfactantconcentrates. More specifically, the examples refer to the followingspecifications and laboratory test methods:

Surface Tension and Interfacial Tension: According to ASTM D-1331-56.Based on laboratory tests, the surface tension of cyclohexane used forcalculating the SC was 24.7 dynes/cm.

The UL 162 Type III, Class B, topside, fire test for AFFF agents wasused to test the 3% synthetic liquid concentrates as premixes in tapwater and synthetic sea water. For each fire test, 55 gallons of heptanewas charged to a 50 ft² heavy steel UL pan with enough water in thebottom to give at least eight inches of sideboard. A US military typeaspirating nozzle adjusted to give a 2.0 gallon per minute flow rate wasplaced on a stand. The fire is lit, allowed to burn for 60 seconds, andthen foam is directed onto the surface of the fuel until the fire isabout 75% extinguished. Then a firefighter picks up the nozzle and movesthe foam stream back and forth until 90% extinguishment (control time)is obtained, at which time the firefighter is allowed to fight the firefrom two sides of the pan. Times are recorded at 90% control and atextinguishment. Foam application is continued for a total of 3 minutes.

At about 8 minutes, a 1.0 square foot steel stovepipe is placed 1.0 ftfrom each side of the corner last extinguished and all foam inside thepipe is removed. After waiting 9 minutes from foam shut-off, the fuelinside the pipe is lit and allowed to burn for 1 minute. The pipe isthen removed and timing of the burnback is started. When the fireincreases to 20% of the pan area, the burnback time is recorded.

Foam quality is measured by taking the expansion ratio and drain timefrom the nozzle after running the fire test.

An AFFF product passes this fire test by extinguishing before 3 minutesand having a burnback equal to or greater than 5 minutes. Strongerproducts give shorter extinguishing and longer burnback times.

The UL 162 Type III, Class B, topside, fire test for Fluoroprotein (FP)agents was used to test the 3% synthetic liquid concentrates as premixesin tap water and synthetic sea water. For each fire test, 55 gallons ofheptane was charged to a 50 ft² heavy steel UL pan with enough water inthe bottom to give at least eight inches of sideboard. A US militarytype aspirating nozzle adjusted to give a 3.0 gallon per minute flowrate was placed on a stand. The fire is lit, allowed to burn for 60seconds, and then foam is directed onto the surface of the fuel untilthe fire is about 75% extinguished. Then a firefighter picks up thenozzle and moves the foam stream back and forth until 90% extinguishment(control time) is obtained, at which time the firefighter is allowed tofight the fire from two sides of the pan. Times are recorded at 90%control and at extinguishment. Foam application is continued for a totalof 5.0 minutes.

At about 14 minutes, a 1.0 square foot steel stovepipe is placed 1.0 ftfrom each side of the corner last extinguished and all foam inside thepipe is removed. After waiting 15 minutes from foam shut-off, the fuelinside the pipe is lit and allowed to bum for 1 minute. The pipe is thenremoved and timing of the burnback is started. When the fire increasesto 20% of the pan area, the burnback time is recorded.

Foam quality is measured by taking the expansion ratio and drain timefrom the nozzle after running the fire test.

A FP product passes this fire test by extinguishing before 5.0 minutesand having a burnback equal to or greater than 5 minutes. Strongerproducts give shorter extinguishing and longer burnback times. It shouldbe noted that FPs when compared with AFFF agents are applied at a rateof 0.06 vs 0.04 gal/ft² and for two minutes longer than AFFF agents; alonger burnback of 21 minutes minimum is required for FPs versus 15minutes for AFFF agents.

Simple 3% synthetic surfactant concentrates were formulated todemonstrate the invention; Examples A-H are given below in Table 1-1 toshow performance enhancement due to HS-100/Magnesium sulfateinteractions.

The Chemguard HS-100 used as the anionic hydrocarbon surfactant is thatmanufactured by Chemguard Inc. at 45% solids in water. Chembetaine CASis used at a 50% solids cocoamidopropyl hydroxypropyl sulfobetane, andis available from Chemron. Mackam 2CYSF is 50% solids octyl dipropionatefrom McIntyre while Deriphat D-160C is 30% solids lauryl dipropionatefrom Henkel. Sulfochem NADS is 30% solids sodium decyl sulfate in waterfrom Chemron. Sulfochem NOS is 40% solids sodium n-octyl sulfate inwater from Chemron. Witcolate 7103 is 60% solids ammonium lauryl ethersulfate from Witco. Magnesium sulfate is charged as the heptahydrate.TABLE 1a Components (as 100%) A B C D E F G H High MW 0 0.9 1.8 2.7 3.63.6 3.6 3.6 Acidic Polymer (HMWAP) HS-100 Chembetaine 0.5 0.5 0.5 0.50.5 0.5 0.5 0.5 CAS Sulfochem 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 NADSHexylene 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Glycol Magnesium 30.0 30.0 30.030.0 30.0 20.0 10.0 5.0 Sulfate Water 61.5 60.6 59.7 58.8 57.9 67.9 77.982.9 3% Tap water solu. Surface 22.5 23.3 24.4 23.9 24.0 23.9 23.0 24.7Tension¹ γ_(b) Interfacial 2.9 3.3 2.3 2.3 2.6 2.3 2.4 3.3 Tension¹γ_(I) Spreading −0.7 −1.9 −2.0 −1.5 −1.9 −1.5 −0.7 −3.3 Coeffic.^(1,2)SC_(a/b)¹units - dynes/cm, with interfacial tension against cyclohexane²γ_(a) = 24.7 dynes/cm

TABLE 1b Components (as 100%) I J K L M N O P High MW 3.6 0 3.6 3.6 3.64.1 4.1 3.6 Acidic Polymer (HMWAP) HS-100 Chembetaine 0 0 0 0 0 0.5 0.50 CAS Mackam 1.5 1.5 1.5 2.8 5.0 0 0 0 2CYSF Deriphat 0 0 0 0 0 0 0 4.8D-160C Sulfochem 0 0 0 0 0 0 0 2.0 NOS Sulfochem 9.0 9.0 6.0 6.0 6.0 7.50 0 NADS Witcolate 7103 0 0 0 0 0 0 7.5 0 Hexylene 2.0 2.0 2.0 2.0 2.02.0 2.0 2.0 Glycol Magnesium 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0Sulfate Water 53.9 57.5 56.9 55.6 53.4 54.0 54.0 59.6

TABLE 1c Components (as 100%) Q R S T U V High MW Acidic Polymer 2.3 1.40 2.5 4.1 4.1 (HMWAP) HS-100 Chembetaine CAS 0 0 0 0 0 0 Mackam 2CYSF1.7 1.7 1.7 1.7 1.3 2.3 Sulfochem NADS 10.5 10.5 10.5 10.5 6.0 9.0Witcolate 7103 0 0 0 0 0 0 Hexylene Glycol 0 0 0 2.0 2.0 0 MagnesiumSulfate 30.0 30.0 30.0 30.0 25.0 15.0 Water 55.5 56.4 57.8 46.0 61.669.6

TABLE 2a UL 162 Type III, Class B, Heptane Fire Tests, 3% Tap, 5 min @0.06 gal/ft² 3% Agents A B C D E F G H HS-100 (%) 0 0.9 1.8 2.7 3.6 3.63.6 3.6 Magnesium 30.0 30.0 30.0 30.0 30.0 20.0 10.0 5.0 Sulfate (%)Heptane, ° F. 63 64 73 68 68 72 55 68 Water, ° F. 59 64 81 79 77 82 5977 Control Time* None 1.8 1.5 1.2 1.0 1.0 1.0 1.5 Extinguish. 60% 3.63.1 2.5 1.9 2.2 2.2 3.0 Time* Foam Cover N/A 50% 95% 100% 100% 100% 95%2% at BB Burnback N/R N/R −0.1 0.8 4.1 2.8 0.7 N/R Time* Foam Exp. 5.86.1 7.8 7.6 8.0 6.3 6.1 6.2 Foam ¼ 2.0 2.3 2.7 2.8 3.0 3.6 3.5 2.6Drain**Time in minutes

TABLE 2b UL 162 Type III, Class B, Heptane Fire Tests, 3% Tap, 5 min @0.06 gal/ft² 3% Agents I J K L M N O P Heptane, ° F. 63 61 68 55 63 6668 63 Water, ° F. 70 68 73 55 66 72 68 75 Control Time* 1.0 None 0.9 1.30.9 0.8 0.9 1.0 Extinguish. 2.1 None 2.5 2.0 2.2 1.7 1.5 2.3 Time* FoamCover 100% N/A 100% 100% 100% 100% 100% 100% at BB Burnback 4.3 N/R 4.65.5 4.8 4.7 4.5 3.7 Time* Foam Exp. 7.0 6.9 6.5 6.5 6.8 7.5 6.3 6.3 Foam¼ 4.1 1.9 4.1 3.6 4.4 3.3 3.0 3.5 Drain**Time in minutes

TABLE 2c UL 162 Type III, Class B, Heptane Fire Tests, 3%, 3 min @ 0.04gal/ft² 3% Agents Q R S T U U V Water Tap Tap Tap Tap Tap Sea Sea WaterWater Heptane, ° F. 61 57 59 63 55 50 57 Water, ° F. 70 63 55 63 64 5057 Control 1.1 1.6 None 0.8 1.0 1.2 0.8 Time* Extinguish. 2.0 2.5 None1.8 1.8 2.3 1.8 Time* Foam Cover 100% 100% N/A 100% 100% 100% 100% at BBBurnback >7.0 1.9 0 >10.0 >8.0 6.8 >8.0 Time* Foam Exp. 8.4 7.3 6.5 8.38.6 7.6 6.5 Foam ¼ 4.7 3.7 3.1 5.8 6.5 3.8 3.6 Drain**Time in minutes

Examples A-E

Examples A through E (Tables 1 a and 2 a) demonstrate a definitiveimprovement in UL 162 type performance when the HS-100 content isincreased from 0 to 3.6% while holding the magnesium sulfate contentconstant at 30%; all other formula components are held constant. Infact, Example A without HS-100 did not control the fire (60%extinguishment at 5.0 minutes) while Example E extinguished at a rapid1.9 minutes, had 100% foam cover at burnback time, and had 4.1 minutesburnback; a vast improvement on increasing HS-100 concentration.Clearly, the performance improved with each increase in the HS-100content going from Example A through E when the magnesium sulfatecontent was held at 30%. Since all other components were held constant,the UL 162 type performance improvement must be due to the HS-100; ahigh molecular weight anionic polymer.

From Examples A-E, it can be seen that there is no correlation betweenthe spreading coefficient (SC) and the fire performance of theformulations. Example A with the least negative SC had the poorestperformance, while Example E had a negative 1.9 SC and performed best inthe series. It can be reasoned that the fire performance is independentof the SC. Therefore, the interaction between the HMWAP and polyvalentsalt must stabilize the foam bubble to the flame and hot fuel ratherthan enhance the surface active properties.

Examples E-H and I, J

Examples E through H (Tables 1 a and 2 a) show a dramatic reduction inperformance as the magnesium sulfate content was reduced from 30% to 5%in increments while holding the HS-100 content at 3.6%. In fact, ExampleH with only 5% magnesium sulfate and 3.6% HS-100 (a high level) wouldextinguish the fire, but at burnback time only 2% of the pan was coveredwith foam. Therefore a burnback could not be run. Certainly, UL 162 fireperformance decreased with each reduction in the magnesium sulfatecontent.

The SCs of Examples F-H, as above, did not correlate with the fireperformance of the formulations. It must again be concluded that thesurface active properties do not control the fire performancecharacteristics of the working invention.

Examples I and J illustrate two formulas utilizing Mackam 2CYSF insteadof Chembetaine CAS, where Example I contains 3.6% HS-100/30% magnesiumsulfate and J has 0% HS-100/30% magnesium sulfate. As in the examplesabove (E&A), even with a high magnesium sulfate content Example Jwithout HS-100 would not even extinguish the fire while Example Iperformed well. Clearly, strong UL162 fire performance requires thatboth HS-100 and magnesium sulfate be at effective levels.

However, various combinations of HS-100 and magnesium sulfate were seento provide enhanced fire performance. Example G with 3.6% HS-100/10%magnesium sulfate demonstrated approximately equivalent performance topreviously presented Example D with 2.7% HS-100/30% magnesium sulfate.Therefore, excellent performance is obtained from lower HS-100 contentformulations if higher quantities of magnesium sulfate are used.

It should be noted that even at 3.6% HS-100/5% magnesium sulfate and0.9% HS-100/30% magnesium sulfate, the fires were extinguished at 3.0and 3.6 minutes; demonstrating the effectiveness of larger quantities ofHS-100 in the presence of low levels of magnesium sulfate or visa versa.Higher quantities of either HS-100 or magnesium sulfate are required forobtaining acceptable burnback performance.

Examples K-M (Tables 1 b and 2 b)

Example K is varied from Example E by only replacing Chembetaine CASwith Mackam 2CYSF at a higher actives level. It can be seen that Mackam2CYSF works well as a replacement for Chembetaine CAS since bothformulations had excellent extinguishment and burnback performance.Examples K-M demonstrate the effect of further increasing levels ofamphoteric hydrocarbon surfactant on UL 162 fire performance. ExamplesK-M represent a series with increasing levels of Mackam 2CYSF amphotericsurfactant. The best performance overall was obtained by Example L with2.8% Mackam 2CYSF. It should be noted that Example L passed allspecifications for the UL 162 fire test including the burnback whichrequires a minimum of 5 minutes for the burnback.

Examples N-P (Tables 1 b and 2 b)

Examples N and O compare formulas having different anionic hydrocarbonsurfactants at the same actives content. It can be seen that 7.5%actives Sulfochem NADS (sodium decyl sulfate, Example N) and Witcolate7103 (ammonium dodecyl or lauryl ether sulfate, Example O) provideequivalent fire performance. Therefore, sodium decyl sulfate andammonium dodecyl ether sulfate work to provide similar performance inthese formulations.

Example P exemplifies a very different hydrocarbon surfactant mixturewith 4.8% actives Deriphat 160C, a sodium lauryl sulfate amphoteric, and2.0% actives Sulfochem NOS, sodium octyl sulfate. Althoughextinguishment was somewhat slower and burnback was shorter than forExamples N&O, good performance was still obtained for such a largechange in the base formula when the HS-100 and magnesium sulfatecontents were 3.6% and 30%, respectively.

Examples Q-S(Tables 1 c and 2 c)

Examples A-P refer to UL fire tests based on the Fluoroprotein (FP) firetest procedure with foam applied at 3 gpm (0.06 gal/ft²) for 5 minutes.Examples Q-U were tested using the AFFF test regime of 2 gpm (0.04gal/ft²) for 3 minutes; a tougher test procedure since only 6 gallons ofpremix is used versus 15 gallons for the FP test. Examples Q-S exemplifythe importance of HS-100 and magnesium sulfate for obtaining AFFF typeUL 162 fire performance. As HS-100 is reduced from 2.3% (Ex. Q), to 1.4%(Ex. R) and finally 0% HS-100 (Ex. S), the performance went fromexcellent, to moderate, to poor. Example Q, however, was a strongproduct meeting all UL 162 fire performance requirements. Even at 39%less HS-100 content, Example R extinguished the fire at 2.5 minutes andgave 1.9 minutes of burnback time. Only at 0% HS-100 did fireperformance properties disappear.

It should be further noted that for Examples Q-S, no solvent wasincluded in the formulation to enhance or stabilize foam, yet excellentfoam quality was produced. Therefore, it is clear that theseformulations do not require the addition of solvent foam boosters.

Examples T-V (Tables 1 c and 2c)

Examples T&U are similar to Example Q, but have the addition of asolvent foam stabilizer, hexylene glycol, and have varied levels ofMackam 2CYSF and Sulfochem NADS. Examples T&U can be seen in Table 2 cto provide exceptional extinguishment at only 1.8 minutes and burnbacktimes greater than 8.0 minutes with tap water. Example U when testedwith sea water gave an extinguishment of 2.3 minutes and 6.8 minutes forburnback; still excellent performance.

Example V demonstrates excellent performance in sea water without theuse of a foam stabilizer and with only 15% magnesium sulfate.Extinguishment was less than 2 minutes and burnback time was greaterthan 8.0 minutes.

These examples demonstrate that the combination of a HMWAP and apolyvalent salt provides UL 162 Class B fire performance using eitherthe AFFF or FP standard conditions.

The UL 162 Type III, Class B fire test recognizes a difference betweenAFFF and FP type fire extinguishing agents. AFFF agents must extinguishin 3.0 minutes or less at an application density of only 0.04 gal/ft²,while FP agents only need to extinguish in 5.0 minutes at an applicationdensity of 0.06 gal/ft². This means 6.0 gallons of premix are used forAFFF while 15.0 gallons of premix are applied for FP agents. As notedabove, however, the burnback requirements for FP agents are more severethan for AFFF agents. FP agents must have a minimum of 21 minutesburnback from time of foam shutoff compared to 15 minutes minimumburnback for AFFF agents.

The fire fighting compositions, as described herein, may be applied tonon-polar liquid hydrocarbons to extinguish or retard fires from suchliquids during burning. The composition may be applied both to thesurface of such liquids or may be introduced below the surface, such asthrough injection. The composition may be applied in combination withother fire fighting agents, if necessary, such as the dual-agentapplication of both foam and a dry chemical or powder fire fightingagents. An example of such a dry chemical or powder agent is thatavailable commercially as Purple K. In such dual application, the firefighting agents may be applied through the use of adjacent or asgenerally concentric nozzles. In some instances, the dry or powder agentmay be applied alone to initially extinguish any flame, with the foambeing applied to prevent reigniting of the fuel.

While the invention has been shown in only some of its forms, it shouldbe apparent to those skilled in the art that it is not so limited, butis susceptible to various changes and modifications without departingfrom the scope of the invention. Accordingly, it is appropriate that theappended claims be construed broadly and in a manner consistent with thescope of the invention.

1. A foam concentrate comprising water and a high molecular weightacidic polymer (HMWAP) and a coordinating salt, the foam concentrateproviding a fire-fighting composition when mixed with water so that thefire-fighting composition does not form a stable seal on cyclohexane andmeets UL 162, Class B performance criteria for at least one of AFFFagents and fluoroprotein (FP) agents without requiring organic fluorine.2. The foam concentrate of claim 1, further comprising: at least one ofa fluorochemical surfactant, an amphoteric hydrocarbon surfactant, ananionic surfactant, a nonionic surfactant, a foaming aid, a freezeprotection agent, a sequestering agent, a buffering agent, a corrosioninhibitor, a polymeric film former, an antimicrobial agent, apreservative, a polymeric foam stabilizer and a polymeric foamthickener.
 3. The foam concentrate of claim 1, wherein: the firefighting composition meets UL 162, Class B performance criteria for bothAFFF agents and fluoroprotein (FP) agents without requiring organicfluorine.
 4. The foam concentrate of claim 1, wherein: the foamconcentrate has a HMWAP content that provides the fire fightingcomposition with from about 0.01 to about 0.3% HMWAP by weight of thefire fighting composition.
 5. The foam concentrate of claim 1, wherein:the foam concentrate has a coordinating salt content that provides thefire fighting composition with from about 0.1 to about 1.5% of thecoordinating salt by weight of the fire fighting composition.
 6. Thefoam concentrate of claim 1, further comprises a fluorochemicalsurfactant, and wherein the foam concentrate has a fluorine contentprovided from the fluorochemical that provides the fire fightingcomposition with less than about 0.006% fluorine by weight of the firefighting composition.
 7. The foam concentrate of claim 1, wherein thefoam concentrate is used in an amount of from about 1 to about 10 partsconcentrate to about 90 to about 99 parts water to form the firefighting composition.
 8. The foam concentrate of claim 1, wherein thefoam concentrate has a fluorine content that provides the fire fightingcomposition with less than about 0.002% fluorine by weight of the firefighting composition.
 9. The foam concentrate of claim 1, wherein thefoam concentrate has a fluorine content that provides the fire fightingcomposition with less than about 0.001% fluorine by weight of the firefighting composition.
 10. The foam concentrate of claim 1, wherein thefire fighting composition has a spreading coefficient againstcyclohexane of zero or less.
 11. The foam concentrate of claim 1,wherein the foam concentrate has a HMWAP content that provides the firefighting composition with from about 0.03 to about 0.2% HMWAP by weightof the fire fighting composition, and wherein the foam concentrate has acoordinating salt content that provides the fire fighting compositionwith from about 0.12 to about 1.2% of the coordinating salt by weight ofthe fire fighting composition.
 12. The foam concentrate of claim 1,wherein the coordinating salt includes those selected from salts andelectrolytes of aluminum, antimony, barium, boron, calcium, copper,iron, magnesium, calcium, strontium and zinc.
 13. The foam concentrateof claim 1, wherein the HMWAP includes those polymers having C4 to C22alkyl branching and having an average MW of from 5000 or greater.
 14. Afire fighting composition comprising water, a high molecular weightacidic polymer (HMWAP) and a coordinating salt, the fire fightingcomposition meeting UL 162, Class B performance criteria for at leastone of AFFF agents and fluoroprotein (FP) agents without requiringorganic fluorine and that does not form a stable seal on cyclohexane.15. The fire fighting composition of claim 14, further comprising: atleast one of a fluorochemical surfactant, an amphoteric hydrocarbonsurfactant, an anionic surfactant, a nonionic surfactant, a foaming aid,a freeze protection agent, a sequestering agent, a buffering agent, acorrosion inhibitor, a polymeric film former, an antimicrobial agent, apreservative, a polymeric foam stabilizer and a polymeric foamthickener.
 16. The fire fighting composition of claim 14, wherein: thefire fighting composition meets UL 162, Class B performance criteria forboth AFFF agents and fluoroprotein (FP) agents without requiring organicfluorine.
 17. The fire fighting composition of claim 14, wherein theHMWAP content is from about 0.01 to about 0.3% by weight of the firefighting composition, and wherein the coordinating salt content is fromabout 0.1 to about 1.5% by weight of the fire fighting composition. 18.A method of extinguishing or retarding a fire comprising: providing afire fighting composition comprising water, a high molecular weightacidic polymer (HMWAP) and a coordinating salt, the fire fightingcomposition meeting UL 162, Class B performance criteria for at leastone of AFFF agents and fluoroprotein (FP) agents without requiringorganic fluorine and that does not form a stable seal on cyclohexane;and applying the composition to an area where extinguishment orretardation of the fire is desired.
 19. The method of claim 18, furthercomprising: applying the composition to the area in combination with adry fire fighting agent.